Department of Earth Sciences, ETH Zürich, 8092 Zürich, Switzerland.
Woods Hole Oceanographic Institution, 360 Woods Hole Road, Falmouth, MA 02543, USA.
Philos Trans A Math Phys Eng Sci. 2023 Nov 27;381(2261):20220328. doi: 10.1098/rsta.2022.0328. Epub 2023 Oct 9.
Compound- and compound class-specific radiocarbon analysis of source-diagnostic 'biomarker' molecules has emerged as a powerful tool to gain insights into terrestrial carbon cycling. While most studies thus far have focused on higher plant biomarkers (i.e. plant leaf-wax -alkanoic acids and -alkanes, lignin-derived phenols), tracing paedogenic carbon is crucial given the pivotal role of soils in modulating ecosystem carbon turnover and organic carbon (OC) export. Here, we determine the radiocarbon (C) ages of glycerol dialkyl glycerol tetraethers (GDGTs) in riverine sediments and compare them to those of higher plant biomarkers as well as markers of pyrogenic (fire-derived) carbon (benzene polycarboxylic acids, BPCAs) to assess their potential as tracers of soil turnover and export. GDGT ΔC follows similar relationships with basin properties as vegetation-derived lignin phenols and leaf-wax -alkanoic acids, suggesting that the radiocarbon ages of these compounds are significantly impacted by intermittent soil storage. Systematic radiocarbon age offsets are observable between the studied biomarkers, which are likely caused by different mobilization pathways and/or stabilization by mineral association. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'.
对源诊断“生物标志物”分子进行化合物和化合物类特异性放射性碳分析，已成为深入了解陆地碳循环的有力工具。虽然迄今为止大多数研究都集中在高等植物生物标志物上（即植物叶蜡 -烷酸和 -烷烃、木质素衍生酚），但鉴于土壤在调节生态系统碳周转和有机碳（OC）输出方面的关键作用，追踪土壤碳至关重要。在这里，我们确定了河流沉积物中甘油二烷基甘油四醚（GDGTs）的放射性碳（C）年龄，并将其与高等植物生物标志物以及源自燃烧（火）的碳的标志物（苯多羧酸，BPCA）进行了比较，以评估它们作为土壤周转和输出示踪剂的潜力。GDGT ΔC 与流域性质的关系与植被衍生的木质素酚和叶蜡 -烷酸相似，表明这些化合物的放射性碳年龄受到间歇性土壤储存的显著影响。在所研究的生物标志物之间可以观察到系统的放射性碳年龄偏移，这可能是由于不同的迁移途径和/或矿物结合的稳定化作用造成的。本文是 Theo Murphy 会议主题“人类世的放射性碳”的一部分。
